I got my iPhone 5 on launch date and today i keep getting a No Sim Card notice on my phone. I can turn off the phone completely and turn it back on and it returns to normal. I then get the message again later in the day, sometimes 20 minutes later sometimes an hour. This happened the first time yesterday, and so far today it has happened about 6 times. Before yesterday no issues at all and in the previous 2 iPhones I had since the launch day of the iPhone 3G it has never happened. I also have had a case on the iPhone 5 since launch day. I am on vacation right now in Key West Florida, from Orlando Florida, so not sure what could be causing this issue. When the SIM card is working normally I am getting 3-4 bars and usually 4G or LTE. I guess when I get back to Orlando I will have to go to AT&T or Apple and have it checked.